Electric sound reproducing apparatus



June 5, 1934. G. s. HOLLY ELECTRIC SOUND REPRODUCING APPARATUS Filed t. 12, 1930 2 Sheets-Sheet 1 June 5, 1934. G. s. HOLLY 1,951,665

ELECTRIC SOUND REPRODUCING APPARATUS Filed Sept. 12, 1930 2 Sheets-Sheet 2 1,7416% Gea ge 5 UNITED STATES PATENT OFFICE ELECTRIC SOUND REPRODUCING APPARATUS George S. Holly, Chicago, Ill., assignor to Stewart-Warner Corporation, Chicago, 111., a corporation of Virginia Application September 12, 1930, Serial No. 481,367

4 Claims. (01. 179--115.5)

This invention relates to a new and improved ing ring 28. The diaphragm 25 is conical in form construction for electric sound reproducing apand provided with a cylindrical extension 29 paratus, and more particularly to the construcwhich carries the voice coil 30. This voice coil is tion of what is commonly called a dynamic loud located in the circular gap between the axial pole 5 speaker, having a movable voice coil carried by piece 16 and the circular opening 31 in the cir- 60 the diaphragm. cumferential pole piece 18. The cylindrical por- It is an object of the present invention to protion 29 and the voice coil are also maintained in vide a reproducer construction in which the diaposition by a spider 32 which is supported from phragm is supported directly from the operating the field plate or circumferential pole piece 18,

structure. by a plurality'of studs 33. The entire assembly 65 It is a further object to provide a construction is shown as supported by a metal supporting in which the axial pole is rigidly and permanently member 34 which may be welded or otherwise selocated with regard to the shell and circumfercured to the lower face of the shell piece 11. ential pole piece. In assembling the speaker, the shell piece is It is also an object to provide a construction formed from a flat strip of suitable magnetizable 7O in which the axial pole and circumferential pole metal, and the openings are punched or drilled piece are maintained in registration by means therein. The axial pole piece 16 is riveted in integral with these pieces. place in the base of the shell piece. The shell It is also an object to provide a construction piece with the pole piece thereon is then located 20 which is composed of but few and simple parts in jigs by means of the holes 20, and a cut is 75 and adapted for commercial production. taken on the outer end of the pole piece to make other and further j t Will app a as t e it perfectly cylindrical and properly centered with description proceeds. regard to the openings 20. The circumferential I have Shown a preferred form f y inv nt-i0 pole piece or field plate 18 is similarly placed in in the accompanying drawings, in which jigs, being located by the integral studs or dowels Figure 1 is a front view of the assembled repro- 19, and a finishing cut is taken in the central ducer; opening 31. The field plate 18 is then assembled Figure 2 is a cross section taken on the vertical on the shell by fitting the dowels 19 into the holes diameter of the reproducer; 20. This assures a perfect registration of the Figure 3 is a plan view of the reproducer; and hole 31 and pole piece 16, so that the end of the 35 i u 4 is a face V w Of e D018 a d She cylindrical pole piece and the circular opening 31 assembly. are absolutely concentric.

In the drawings, the shell piece 11 is provided Since the center of the axial pole piece is perwith the flat base portion 12, the parallel pormanently riveted to the shell and the shell is tions 13, the outturned shoulders 14, which are formed of heavy rigid material, this alignment 90 substantially parallel to the base 12, and. with the will be maintained and it is unnecessary to prooutwardly flared portions 15. The axial pole vide any of the spacing elements which have been piece 16 is riveted to the center of the shell piece used in various prior constructions. The fact at 17. The circumferential pole piece, or field that the diaphragm is also directly secured to plate, 18, is provided with the integral studs or rigid extensions of the shell assures that they will 95 dowels 19, which fit into corresponding holes 20 be perfectly centered. They will be maintained in the shoulders 14 of the shell piece. The screws in the proper position by the spider 32. As clear- 21 pass through the dowels l9 and secure the cirly shown in the drawings, the shell piece is merely cumferential pole piece rigidly to the shell piece. a metal strip so that the diaphragm supporting The magnetizing coil 22 surrounds the axial pole ring 24 is only supported at two points. The 100 piece 16, within the parallel portions 13 of the sides of the diaphragm are entirely unenclosed shell piece. A washer 23, which may be of cardand the diaphragm is permitted to vibrate freely board, felt, or other material, is placed between without any air cushioning effect due to an enthe magnetizing coil 22 and the field plate 18 to closing support. i hold the coil against movement. While I have shown one preferred embodiment 105 The ring 24 is welded to the outer edges of the of my invention, it is capable of change and modiflaring portions 15 of the shell piece. The diafication to meet varying conditions, and I conphragm 25 is secured to the ring 24 by means of template such changes and modifications as come rivets 26, the diaphragm being secured between Within the spirit and scope of the appended claims.

I gaskets 27 which are held in place by the clamp- I claim: n

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1. In an electric sound reproducing construction, a shell piece having a base portion, spaced parallel portions and shoulders parallel to the base portion, an axial pole piece permanently secured to the base portion between the parallel portions of the shell piece, a circumferential pole piece secured to the shell piece and having an opening surrounding the outer portion of the axial pole piece, the circumferential pole piece fitting against the shoulders of the shell piece, means integral with the shell piece and circumferential pole piece for positively maintaining said parts in registration, the shell piece having flaring end portions beyond the shoulders, a diaphragm supported from the end portions. and a voice coil carried by the diaphragm between the axial pole piece and circumferential pole piece.

2. In an electric sound reproducing construction, a shell piece having a base portion, spaced parallel portions and shoulders parallel to the base portion, an axial pole piece permanently secured to the base portion between the parallel portions of the shell piece, a circumferential pole piece secured to the shell piece and having an opening surrounding the outer portion of the axial pole piece, the circumferential pole piece fitting against the shoulders of the shell piece, means integral with the shell piece and circumferential pole piece for positively maintaining said parts in registration, the shell piece having flaring end portions beyond the shoulders, a diaphragm supported from the end portions, a voice coil carried by the diaphragm between the axial pole piece and circumferential pole piece, and a spider for locating the voice coil, said spider being supportfrom the circumferential pole piece.

3. In an electric sound reproducing construction, a shell piece consisting of a flat strip of metal bent to form a fiat base portion with opposite ends bent upwardly at substantially right angles to the base portion and then bent outwardly to form shoulders parallel to the base portion, a cylindrical axial pole piece permanently secured to the center of the base portion and extending between and parallel to the bent up portions of the shell piece, a circumferential pole piece seated on the flat shoulders of the shell piece, said members being provided with interfitting dowels and recesses whereby the parts are maintained in registration, the opposite ends of the shell piece beyond the shoulders being flared outwardly, and a diaphragm supported from said ends.

4. In an electric sound reproducing construction, a shell piece having a base portion, spaced parallel portions and shoulders parallel to the base portion, an axial pole piece permanently secured to the base portion between the parallel portions of the shell piece, a circumferential pole piece secured to the shell piece and having an opening surrounding the outer portion of the axial pole piece, the circumferential pole piece fitting against the shoulders of the shell piece, the shell piece having outwardly extending end portions beyond the shoulders, a diaphragm supported from the end portions, and a voice coil carried by the diaphragm between the axial pole piece and the circumferential pole piece.

GEORGE S. HOLLY. 

